303  
FXSA20 KWBC 061414  
PMDSA  
 
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
914 AM EST MON NOV 06 2017  
 
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/  
 
SYNOPSIS (VALID FROM NOV 06 AT 0000 UTC): THE 200 HPA ANALYSIS  
SHOWS AN UPPER LEVEL RIDGE TRAVERSING NORTHERN SOUTH AMERICA. THE  
RIDGE SPANS BETWEEN THE EASTERN TROPICAL PACIFIC TO THE WESTERN  
ATLANTIC...CROSSING CENTRAL/SOUTHERN PERU-BOLIVIA-SOUTHEAST BRASIL  
WHILE CENTERING ON A CLOSED HIGH AT 14S 57W. THE RIDGE UNDERCUTS A  
TROUGH TO THE NORTH THAT EXTENDS OVER NORTHERN PARA-GUIANAS...AND  
CENTERS ON A CLOSED LOW NEAR THE AMAZON RIVER DELTA. THE TROUGH  
ALOFT FAVORS A CONVERGENT PATTERN THAT IS INHIBITING ORGANIZED  
CONVECTION ACROSS NORTHEAST BRASIL...WHILE THE RIDGE IS VENTING  
DEEP CONVECTION ACROSS CENTRAL-NORTHWEST BRASIL...PERU...BOLIVIA  
AND ECUADOR.  
 
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH ENTRANCE AT  
44S 96W...THEN ALONG 44S 88W...49S 85W...EXITING AT 54S 87W. IT  
REFORMS AT 72S 59W...THEN ALONG 64S 53W...55S 53W...EXITING AT 47S  
50W. IT REFORMS AT 43S 45W...THEN ALONG 44S 31W...50S 21W...AND  
ALONG A 159KT MAXIMUM AT 56S 10W. THE NORTHERN POLAR LIES ALONG  
36S 120W...A 143KT MAXIMUM AT 37S 116W...A 144KT MAXIMUM AT 36S  
103W...34S 91W...EXITING AT 38S 79W. IT REFORMS AT 40S 71W...ALONG  
37S 63W...EXITING AT 36S 59W. THE NORTHERN POLAR HAS A BRANCH TO  
THE EAST WITH ENTRANCE AT 37S 44W...THEN ALONG A 128KT MAXIMUM AT  
41S 31W...46S 19W...EXITING AT 52S 07W. THE SUBTROPICAL JET LIES  
ALONG 33S 120W...33S 109W...A 134KT MAXIMUM AT 32S 100W...EXITING  
AT 26S 90W. IT HAS A FINGER THAT LIES BETWEEN 16S 82W AND 18S 75W.  
THE SUBTROPICAL JET REFORMS AT 24S 62W...THEN ALONG 28S 52W...A  
138KT MAXIMUM AT 31S 40W...31S 28W...24S 20W...EXITING AT 16S 21W.  
 
AT 500 HPA...BROAD TROUGH EXTENDS OVER THE SOUTH PACIFIC BETWEEN  
140W-80W AND TO THE SOUTH OF 30S. THIS IS PRESSING AGAINST A RIDGE  
TO THE EAST THAT EXTENDS FROM SOUTHERN PATAGONIA IN ARGENTINA TO  
THE ANTARCTIC PENINSULA. THIS...IN-TURN...SUSTAINS THE NORTHWARD  
AMPLIFICATION OF A LONG WAVE TROUGH OVER THE SOUTH ATLANTIC. THE  
TROUGH BOUNDS BETWEEN 55W-10W AND TO THE SOUTH OF 30S.  
 
AT LOW LEVELS...A BROAD TROUGH LIES OVER THE SOUTH PACIFIC. POLAR  
FRONTS REVOLVE AROUND THIS AXIS WITH ONE EXTENDING FROM AN  
OCCLUDED 966 HPA LOW AT 57S 104W...THEN ALONG A 968 HPA LOW AT 59S  
104W...58S 95W...55S 90W...A 990 HPA LOW AT 51S 87W...46S  
83W...38S 87W...AND 35S 94W. THIS IS PHASING WITH AN ELONGATED  
FRONT TO THE NORTH THAT EXTENDS FROM A 1014 HPA LOW AT 41S  
80W...THEN ALONG 35S 83W...31S 88W...ISLA DE PASCUA...AND 25S  
117W. A RIDGE TO THE EAST CENTERS ON A 1025 HPA HIGH AT 47S  
62W...WHILE A 1021 HPA HIGH CENTERS AT 35S 49W. OVER THE  
CONTINENT...A 1018 HPA LOW AT 40S 61W EXTENDS A FRONT ALONG 37S  
59W...35S 61W...A 1014 HPA LOW AT 37S 67W...35S 66W...33S 67W...A  
1014 HPA LOW AT 33S 72W...27S 74W...23S 83W...TO 23S 86W. THIS  
SUSTAINS MODERATE RAINFALL ACROSS CENTRAL ARGENTINA. BROAD TROUGH  
OVER THE SOUTH ATLANTIC CENTERS ON A 946 HPA LOW AT 62S 22W. THIS  
SUSTAINS AN ELONGATED FRONT THAT EXTENDS ALONG A 1006 HPA LOW AT  
47S 15W...44S 14W...41S 19W...A 1010 HPA LOW AT 38S 23W...35S  
24W...34S 27W...A 1010 HPA LOW AT 32S 32W...27S 36W...RIO DE  
JANEIRO-SOUTHERN MINAS GERAIS...MATO GROSSO DO SUL TO SANTA CRUZ  
IN EASTERN BOLIVIA.  
 
OVIEDO...SHN (ARGENTINA)  
VANNUCCI...SMN (ARGENTINA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  

 
 
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